This photo released by Tokyo Electric Power Company
shows a fire burning near the Fukushima Dai-ichi power plant's Unit 4 reactor,
April 11, 2011.

TOKYO — Japan's nuclear regulators raised the severity
level of the crisis at a stricken nuclear plant Tuesday to rank it on par
with the 1986 Chernobyl disaster.

An official with the Nuclear Safety Commission of
Japan, speaking on national television, said the rating was being raised
from 5 to 7 — the highest level on the international scale.

The official, who was not named, said the amount of
radiation leaking from the Fukushima Dai-ichi nuclear plant was around 10
percent of the Chernobyl accident.

The level 7 signifies a "major accident"
with "wider consequences" than the previous level, according to
the standards scale.

"We have upgraded the severity level to 7 as
the impact of radiation leaks has been widespread from the air, vegetables,
tap water and the ocean," said Minoru Oogoda of Japan's Nuclear and
Industrial Safety Agency.

NISA officials said one of the factors behind the
decision was that the total amount of radioactive particles released into
the atmosphere since the incident had reached levels that apply to a Level
7 incident.

The action lifts the rating to the highest on an international
scale designed by an international group of experts in 1989 and is overseen
by the International Atomic Energy Agency.

In Chernobyl, in the Ukraine, a reactor exploded on
April 26, 1986, spewing a cloud of radiation over much of the Northern Hemisphere.
A zone about 19 miles around the plant was declared uninhabitable, although
some plant workers still live there for short periods and a few hundred
other people have returned despite government encouragement to stay away.

Meanwhile, setbacks continued at Japan's tsunami-stricken
nuclear power complex, with workers discovering a small fire near a reactor
building Tuesday. The fire was extinguished quickly, the plant's operator
said.

Tokyo Electric Power Co., which operates the disabled
Fukushima Dai-ichi nuclear power plant, said the fire at a box that contains
batteries in a building near the No. 4 reactor was discovered at about 6:38
a.m. Tuesday and was put out seven minutes later.

It wasn't clear whether the fire was related to a
magnitude-6.3 earthquake that shook the Tokyo area Tuesday morning. The
cause of the fire is being investigated.

"The fire was extinguished immediately. It has
no impact on Unit 4's cooling operations for the spent fuel rods,"
said TEPCO spokesman Naoki Tsunoda.

The plant was damaged in a massive tsunami March 11
that knocked out cooling systems and backup diesel generators, leading to
explosions at three reactors and a fire at a fourth that was undergoing
regular maintenance and was empty of fuel.

The magnitude-9.0 earthquake that caused the tsunami
immediately stopped the three reactors, but overheated cores and a lack
of cooling functions led to further damage.

Engineers have been able to pump water into the damaged
reactors to cool them down, but leaks have resulted in the pooling of tons
of contaminated, radioactive water that has prevented workers from conducting
further repairs.

Aftershocks on Monday briefly cut power to backup
pumps, halting the injection of cooling water for about 50 minutes before
power was restored.

TOKYO (Reuters) - Slight amounts of strontium, a heavy
radioactive metal that could lead to leukemia, have been detected in soil
and plants near the crippled Fukushima Daiichi nuclear plant, Japan's science
and technology ministry said on Tuesday.

Japan has already detected radioactive elements including
iodine, cesium and plutonium, in areas near the plant operated by Tokyo
Electric Power after reactors there were crippled due to a loss of power
that disabled cooling functions.